From 6aed15e330bfec6a423f40582b2a8b53d9ce1757 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Wed, 1 Feb 2023 11:30:16 -0600 Subject: selftests/bpf: Add testcase for static kfunc with unused arg kfuncs are allowed to be static, or not use one or more of their arguments. For example, bpf_xdp_metadata_rx_hash() in net/core/xdp.c is meant to be implemented by drivers, with the default implementation just returning -EOPNOTSUPP. As described in [0], such kfuncs can have their arguments elided, which can cause BTF encoding to be skipped. The new __bpf_kfunc macro should address this, and this patch adds a selftest which verifies that a static kfunc with at least one unused argument can still be encoded and invoked by a BPF program. Signed-off-by: David Vernet Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20230201173016.342758-5-void@manifault.com --- net/bpf/test_run.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net/bpf') diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index af9827c4b351..e6f773d12045 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -741,6 +741,11 @@ __bpf_kfunc void bpf_kfunc_call_test_destructive(void) { } +__bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) +{ + return arg; +} + __diag_pop(); BTF_SET8_START(bpf_test_modify_return_ids) @@ -779,6 +784,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2) BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg) BTF_SET8_END(test_sk_check_kfunc_ids) static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size, -- cgit v1.2.3-58-ga151